Tangents of A Genius
by AstroPhantom
Summary: Cassie finally gets to see who Danny really is, and now she an indispensable part of Team Phantom. A collection of my Cassie one-shots (for now)...
1. Positive Direction

**Positive Direction**

* * *

Cassie's mouth felt beyond dry in the afternoon summer heat as she knocked rapidly on the Foleys' front door, itching to get into the air-conditioned town house. Even the ring on her finger seemed like a traitorous ally of the heat, the sweat beneath it making it all too easy for her to spin it around with her thumb. At least the extra layer of the swimsuit underneath her clothes provided reassurance of the relief to come at the pool park later.

At last, Tucker's mom, Angela answered the door, smiling down cheerfully at her son's girlfriend. "Hi, Cassie. Come on in!" She moved to the side to let her pass.

"Thanks, Mrs. Foley," Cassie answered, letting the cool air of the AC fall over her as she walked into their living room.

Angela closed the door, ushering the new arrival towards the stairs. "Tucker should be back in his room soon. You can go on up though. I'm going to bring some lemonade up in a bit for you guys as soon as I finish making it."

Cassie grinned to herself. She couldn't help but love the way Angela was always so friendly and inviting, and always made something if she knew Tucker had friends coming over. "Sounds great! I'll head up now then."

She began the trek up the stairs as Mrs. Foley disappeared into the kitchen. She couldn't wait to see Tucker, and Sam and Danny again. The Apple Store had changed her hours around this past week, so this was her first real chance in a few days to hang out with them. That, and to cool off from the massive heat wave that had swept over Amity Park by taking refuge in a nice cold pool.

Tucker's door was closed in a way that suggested vacancy, but Angela had given her permission to wait for him in there. Without another thought, Cassie turned the knob and opened the door wide to see the technogeek's haven. The bed was barely made and there was the pervasive hum of a handful of electronic devices surrounding his desk. Ah, Tucker.

Halfway to the bed to sit down on the mattress, Cassie let out a shrill squeak and stumbled backwards into the wall.

The infamous Danny Phantom had popped up out of nowhere through the floor, eyes closed as he rambled on, "Tucker! I brought your goggles! Again! And Sam should be here in five."

What had she just seen? In one second, her fury had begun to instantly grow behind a more instinctive defensive stance at the intruder, confused as to why the ghost was talking so casually to an absent Tucker. And in the next, a pair of blinding white rings of light had enveloped Phantom, leaving…Danny Fenton in their wake?

Wait? Fenton was Phantom?! Danny Fenton, her boyfriend's best friend, was _Phantom_? Is that what she had just seen? They had started dating nearly three months ago, and Tucker had failed to mention that his best friend was the destructive ghost boy?!

Danny caught sight of her finally, the goggles dropping from his hand in surprise. "Oh shit. Cassie, wait, I can explain. I can-"

Tucker bounded into his room. "Hey guys, I thought I heard a voice, and–oh. Oh god, no." He saw the look of anger on Cassie's face, which was now directed at him, and the nervous, caught-in-the-headlights expression on Danny's.

Cassie didn't hesitate to poke Tucker firmly in the chest, her glasses reflecting light from the hallway. "How in the world could you not tell me Danny is Phantom?! Huh? We've been together for a few months and you didn't bother to mention that your _friend_ is…is a _ghost_?!"

"Technically a half-ghost," Danny chimed in.

"Shut it, you freaky jerk," Cassie glared at him from over her shoulder. "How could you not tell me _this_?"

"Hey! Don't call him that!" Tucker defended.

She brushed off the warning, crossing her arms. "Explain yourself. And him."

Tucker's back was now against the wall. His eyes shifted between hers and Danny's, which gave him a "might as well tell her" look. He sighed, then straightened himself up so that he was towering a few inches over her. "Okay, yes. Danny's Phantom and Fenton. Same dude. There was an accident a few years ago in his parents' lab, and…he became half-ghost somehow." He took ahold of Cassie's shoulders. "Look, I'm-we're sorry we didn't tell you. But we didn't want to put you in any danger!"

"But we're all in danger around him!" She jerked a thumb over her shoulder, gritting the last few words out between her teeth. Her brain was still processing the situation, but she stood resolute in her perception of Phantom.

"No, we're not! He's a good guy! He doesn't hurt people!"

"Yes, he _does_!"

"No, he _doesn't_!"

The couple stared at each other, neither refusing to back down. Tucker was upset that she had jumped to conclusions so quickly, while Cassie felt the heartbreak of betrayal looming near. Danny stood silently, legs braced against Tucker's bed, giving the two their space.

Cassie spoke up first, her voice quivering. "You know, if I can't trust you to not keep secrets like this from me, then maybe I should just go-"

"No," Tucker cut her off, sounding slightly miffed that she wanted to leave over this. "Don't leave. Listen, I'm sorry you found out like this, but Danny _is_ a good guy. He fights off the bad ghosts and protects Amity Park." He took her hand gently and guided her to sit in his desk chair. "Why do you think Danny's such a bad guy?"

Cassie glared ruefully at Danny, before letting her hands grip her knees as she talked to the carpet beyond them. "I don't think, I _know_. It was during that town meeting a couple years back, you know, during that huge ghost invasion? Well, my mom was there, and she brought my little brother, Harrison, along, because my other mom was working and I was at a friend's house."

Tucker sat down on the edge of his bed, nodding for her to continue as he took the information in. Danny was looking fastidiously down as he scoured over the events of the invasion, trying to foreshadow where her story was going.

She continued, "My mom said that when Phantom came in and started attacking the mayor, everyone was running around trying to get away from him and the other ghosts and that there was a lot of pushing and shoving. And…she and Harrison got stuck in the crowd at some point, and all she saw was Phantom flying past her into the ground before part of one of those big ceiling lights fell down a-and hit them. Crushed them. My mom took the brunt of it. It fractured her shoulder-blade and she broke some fingers somehow covering Harrison, and he sprained his arm. He was so afraid for weeks afterward. But all my mom said she could keep thinking about was that _damned_ Phantom ghost flying around so recklessly trying to break everything in sight."

Cassie looked up at her audience, finally realizing that she'd started to tear up at some point, her glasses fogging up a bit. She still couldn't get over what happened to her little brother, but now that she was in front of the culprit himself? She had to physically and mentally restrain herself from lashing out.

"Dammit, Walker," Danny sighed. Tucker shook his head in disgust at the memories, before Danny began explaining, "Cassie, listen. I swear on my own half-grave that it wasn't me that broke the light. I was trying to stop the bad ghosts. The mayor was overshadowed by this jail warden ghost, Walker, and I was trying to get him out. I didn't break the light though, that must've been one of his goons."

"It's kinda funny actually," Tucker quipped, before hastily explaining the humor. "Walker's original plan then was to get the whole town to hate you, Danny. Two years later, and it's still working."

"Heh, yeah. But I swear to you, Cassie, I didn't break the light." Danny looked at her hopefully.

Unfortunately for him, Cassie still seemed unconvinced. "Well, if you're such a good guy, then how come you didn't save my mom and brother?"

This question elicited another sigh from Danny, his hand going to the back of his neck awkwardly. "To be honest, I didn't even know about the light. When I disappeared through the ground, I was chasing Walker into the basement. You said the light dropped after me. I had no idea about it. But you gotta believe me, if I had known, I would have saved your family first. Now that I know, I hate that I couldn't. I'm sorry, to you and them." He kicked at the ground.

Cassie's expression softened slightly. Apparently she had been too quick to jump to conclusions and assumptions. The fact that he would have saved them if he knew eased her grudge immensely. It must have just been a wrong place, wrong time moment. "I-thank you, Danny. And I'm sorry. That I jumped to conclusions."

She smiled apologetically at Danny, before turning to Tucker with a distrustful look back on her face. He seemed to cower into himself. "As for you, Tucker…I still don't know why you would keep such a bombshell secret from me!"

"Like I said earlier, we wanted to keep you safe and out of danger. I'm sorry we didn't tell you, but it was for your own good," Tucker answered. "And besides, no one outside of our group is supposed to know about him, and I…I wasn't sure where exactly we…us…were going yet." He picked nervously at the edge of his shorts, refusing to meet her gaze.

Cassie's eyes widened in surprise. They were boyfriend and girlfriend, but they had never really talked too far into the future. She smirked to herself at Tucker's adorable awkward gestures, before walking over to him and firmly planting her lips on his. "I'd like to think we're going in a positive direction now. Sorry I lashed out."

Tucker shyly searched her eyes, finding genuine truth in them. "It's okay. And good, 'cause I already bought your ticket to the water park." He was met with a playful slap on his shoulder, before he hugged Cassie vigorously.

"I'd hate to interrupt this week's soap, but we should get going to said water park." Everyone jumped at Sam's voice, who was standing in the doorway. She shrugged herself off the frame and made her way over to kiss Danny, before turning to Cassie. "Welcome to Team Phantom, Cassie. Glad you can trust Tucker again, but now you need to worry about mine. Fair warning and rule number one: you can't tell another soul about Danny. We all have to protect his identity. But if you do, then…Tucker will suffer because my boyfriend is."

Tucker half-laughed, half-yelped at Sam's bold statement, but knew she was serious when it came to Danny. He turned back to Cassie. "What do you say, baby? Can I trust you to keep Sam's trust?"

She pecked his nose protectively. "Absolutely."

* * *

 _This was a mix of an idea I had for revealing Phantom to Cassie and a prompt for Cassie and Tucker's first fight._

 _If you're lost as to who Cassie is, she's my OC girlfriend for Tucker from my "Never" series that you should totally read. ;P_

 _A sort-of sequel coming VERY soon!_


	2. And Many More

**And Many More**

* * *

"…it's here because Tucker said that Cassie said that her parents said that they don't want to miss out on her eighteenth birthday. She's their first-born."

"I still think our surprise party for her on Saturday will be better. Family parties are always too weird and awkward."

"No, Sam, YOUR family parties are awkward. This is Cassie's family, not your parents, okay? Not all families are hellbent on forcing their daughter to wear pink dresses. You're safe here from all pink and all dresses."

Sam stopped Danny in his tracks to make him look at her. "And if I'm not?"

He leaned down to breathe in her ear. "If you're not, then after the party I'll make sure you're far away and safe from _any_ dresses. I might have to qualify your skirt into the dress category as well."

Danny smirked as he walked the few remaining steps to Cassie's door, taking pride in how Sam seemed to lag behind, completely speechless. "Coming?"

Sam shook her head to break herself out of her mind, catching up with Danny and giving him a playful shove in the shoulder. He rang the doorbell, which was almost immediately answered by Tucker.

"Hey guys! Party's in the back, come on!" Sam and Danny followed their friend to the backyard, where a series of string lights illuminated about twenty people chatting over the scent of barbecue.

"Right. Meat eaters," Sam grumbled.

"Aw, it's okay, baby. I think I see some fruit and veggie platters over there. Let's go!" Danny guided themselves through the crowd so they could make their plates.

* * *

About half an hour later, Danny and Sam were sitting comfortably across from Tucker and Cassie, talking about seeing a movie on Saturday, at least to Cassie's knowledge. The plan was to meet at Sam's house, six o'clock sharp and then, "see" _Zombie-Wolf_.

" _Happy Birthday to you, happy birthday_ …" Without a warning, Cassie's family had surrounded the four of them, singing slightly off-key but cheerfully nonetheless. Cassie's moms were carrying a homemade chocolate-frosted cake, littered with flaming candles, towards her, with her little brother, Harrison, close on their heels. Tucker, Sam, and Danny leaned off the table, joining in the singing as they smiled at their friend.

Almost as soon as the merriment had begun, however, it was just as quickly in jeopardy of being ended early. Danny was the first to see it. Well, him.

Danny quickly nudged Sam to his left, nodding towards the intruder. There he was, behind Cassie's family, sneaking around the corner of the house, towards…the table of presents. Of course.

Danny shook his head. Next time he would make sure to _not_ speak of any party plans when he was catching ghosts. Namely, the Box Ghost.

The song couldn't end soon enough. As soon as Cassie blew out the candles and cut the first slice, Danny and Sam silently excused themselves from the commotion, tapping on Tucker's shoulder as they went to make him aware of the situation. They made their way into the house, finding Cassie's room on the second story easily.

"Got the thermos?" Danny asked, not hesitating to transform to Phantom once the door was locked. The green of his eyes bounced off the walls.

"Uh…no," Sam admitted as she came up empty-handed from searching her backpack. "I think I left it in my car."

"Alright, just get the thermos and meet me in front of the garage. It looked pretty secluded." With that, Danny turned invisible and phased through the outside wall.

It only took a matter of seconds before he found the Box Ghost. Thankfully, all the party guests still seemed distracted by the cake, music, and each other, save for Tucker who was carefully watching the scene. The Box Ghost seemed to be taking his time as he levitated a few of the boxed presents, grinning maniacally and laughing to himself. As he turned to his right to move some of the boxes, he spotted Danny–flying towards him at lightning speed.

Danny's body slam sent the two of them careening full force towards the yard fence, the presents toppling down on the table carelessly. He phased the two of them through the wood before dragging him to the driveway in the front.

"Beware!"

Danny cut off the familiar cry before the blue ghost had a chance to say anything further. "Man, just stop right there. I'd be insanely rich if I had a dollar for every time I've heard that. Now, stop messing with my friend's girlfriend's party!"

"Oh, you know I cannot resist boxes. They will soon be mine!" the Box Ghost retorted, his eyes starting to glow as he lunged for Danny.

Phantom side-stepped the attempt easily, turning to grab the obnoxious ghost by the back of his overalls. "This is seriously not the place, dude." He saw Sam approach from the sidewalk, thermos waiting in hand. "Time for you to go."

Sam pressed the capture button on the side of the Fenton Thermos, watching the blue light envelope the Box Ghost and suck him in hungrily. She spoke up to the floating Danny, "The sad part is, this didn't even challenge the most exciting party invasion we've ever faced."

"I don't think _anything_ will ever top Desiree. Come on." Danny grabbed Sam by the waist and phased them back into Cassie's room.

Not two seconds later, Tucker and Cassie burst through her door. Cassie looked confused, above all else. "What _was_ that?!"

Danny answered as he changed back into his human form, holding protectively onto the thermos. "The Box Ghost. He's pretty harmless. Usually. Sorry about that though. He likes parties because of the presents."

"Which, for him, are just the boxes," Tucker added. "Anyway, we rearranged the presents down below, so no one suspects anything."

"Perfect. And don't worry, Cassie. No other ghosts should start showing up here. That was kind of my fault. Slip of the tongue. But just in case," Danny exchanged a look with Sam, who pulled a small box with a bow on top of it out of her backpack. "We figured we should give this to you now."

Cassie hesitantly pulled the lid off the box, taking in the gleaming silver metal interlaced with neon green highlights.

Sam picked up where Danny left off. "It's a Fenton Wrist-Ray. It's not much, but if you ever do run into a ghost, it should fend them off."

The device beeped to life as Tucker helped Cassie activate it on her wrist. "Consider it a 'Welcome to Team Phantom' present. We'll show you more of the ropes another time, but for now, this should do the job."

Cassie glanced around her room, noticing the subtle seriousness under everyone's expressions. "You know, most people are thinking about college and adult life on their eighteenth birthday. I got the bonus of learning how to fight off ghosts. This should be interesting."

"And then some. But for now, let's go finish off that eighteenth birthday, hmm?" Tucker offered his arm to his girlfriend, leading her downstairs to the party.

Sam and Danny only heard the beginning of Cassie's reply as the two disappeared around the corner. "It's the 'and then some' I'm worried about."

* * *

 _So now that Cassie_ _knows about Danny, she's gonna be seeing and doing a whole lot more._

 _And thanks to all that have left me such awesome reviews! I'll be getting to those very soon, but hey...this was the last story from my Tumblr I had to upload! I'm up to date! So everything from here on out will be fresh and new (but I'll still be posting to Tumblr first)!_

Thank you again for all the support!


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